Re #8357. Remove leak in test by adding components to instrument.

The fact that you have to call two methods in succession to get this
right is probably not great design. Nor is the fact that you can
'mark' something that isn't in the instrument without any error or warning.

Code/Mantid/Framework/API/test/ExperimentInfoTest.h

@@ -710,11 +710,15 @@ class ExperimentInfoTest : public CxxTest::TestSuite
     ExperimentInfo_sptr exptInfo(new ExperimentInfo);
     boost::shared_ptr<Instrument> inst1(new Instrument());
     inst1->setName("MyTestInst");
-    inst1->markAsSource(new ObjComponent("source"));
+    auto source = new ObjComponent("source");
+    inst1->add(source);
+    inst1->markAsSource(source);
 
     for(size_t i = 0; i < npoints; ++i)
     {
-      inst1->markAsChopperPoint(new ObjComponent("ChopperPoint"));
+      auto chopperPoint = new ObjComponent("ChopperPoint");
+      inst1->add(chopperPoint);
+      inst1->markAsChopperPoint(chopperPoint);
     }
     exptInfo->setInstrument(inst1);
     return exptInfo;